1. Field of the Invention
The present invention relates to a rotary compressor used, for example, in an air conditioner.
2. Description of the Related Art
In a conventional rotary compressor, first and second groove portions 563S and 563T (see FIG. 7) are formed in a lower end plate 160S and an upper end plate 160T of a compressing unit 12 (see FIG. 1), respectively. The first and second groove portions 563S and 563T accommodate reed valve type first and second discharge valves 200S and 200T, which open and close first and second discharge openings 190S and 190T, and first and second discharge-valve limiters 201S and 201T, which are used to limit valve-opening amount of the first and second discharge valves 200S and 200T when they are deflected (hereinafter, deflection opening amount of the first and second discharge valves 200S and 200T), respectively. Furthermore, the first and second groove portions 563S and 563T are formed such that the first and second discharge valves 200S and 200T and the first and second discharge-valve limiters 201S and 201T are attached with first and second rivets 203S and 203T, respectively (see FIGS. 7 and 8).
On the side the first and second discharge openings 190S and 190T of the first and second groove portions 563S and 563T, the diameter (width) of the first and second groove portions 563S and 563T is enlarged so as to form first and second discharge-opening-side enlarged diameter portions 563Sb and 563Tb, respectively. Also on the side of the first and second rivets 203S and 203T, the diameter (width) of the first and second groove portions 563S and 563T is enlarged so as to form first and second rivet-side enlarged diameter portions 563Sa and 563Ta, respectively.
As illustrated in FIG. 8, the first and second discharge valves 200S and 200T and the first and second discharge-valve limiters 201S and 201T are attached to the inside of the first and second groove portions 563S and 563T (the first and second rivet-side enlarged diameter portions 563Sa and 563Ta) with the first and second rivets 203S and 203T inserted into first and second rivet holes 191S and 191T, respectively. The first and second rivet holes 191S and 191T are provided in the bottom portions of the first and second rivet-side enlarged diameter portions 563Sa and 563Ta, respectively.
The first and second discharge-opening-side enlarged diameter portions 563Sb and 563Tb are formed by enlarging the diameter (width) of the first and second groove portions 563S and 563T, respectively. That is, the first and second discharge-opening-side enlarged diameter portions 563Sb and 563Tb have a diameter (width) which is larger than that of the first and second groove portions 563S and 563T, respectively. Consequently, a path of compressed refrigerant gas is formed through which the compressed refrigerant gas discharged from the first and second discharge openings 190S and 190T ejects pushing open the first and second discharge valves 200S and 200T, respectively.
At the first and second rivet-side enlarged diameter portions 563Sa and 563Ta, the first and second groove portions 563S and 563T are enlarged to have a diameter (width) Ha which is larger than that of the first and second groove portions 563S and 563T. This prevents a punch P of a swaging machine (not shown) from interfering with an inner wall portions of the first and second rivet-side enlarged diameter portions 563Sa and 563Ta, when swaging, i.e. pressing or applying pressure by the punch P to cause plastic deformation, first and second swaging portions 203Sa and 203Ta of the first and second rivets 203S and 203T. As illustrated in FIG. 9, when the first and second swaging portions 203Sa and 203Ta are swaged, the swaging machine presses a tip N of the punch P against the first and second swaging portions 203Sa and 203Ta and make the punch P perform a rosette-like axial motion (motion of moving on a conical petal-like trajectory Y) about the central axis Z of the first and second rivets 203S and 203T in order to swage the first and second swaging portions 203Sa and 203Ta.
The thickness ts of the bottom portions of the first and second groove portions 563S and 563T (including the first and second rivet-side enlarged diameter portions 563Sa and 563Ta and the first and second discharge-opening-side enlarged diameter portions 563Sb and 563Tb) is made as thin as possible so as to prevent backflow of the compressed refrigerant gas trapped in the first and second discharge openings 190S and 190T toward first and second operating chambers 130S and 130T (see FIG. 2) and prevent the volumetric efficiency of refrigerant compression from decreasing.
In a conventional hermetic type compressor (rotary compressor) including a cylinder chamber formed from a cylinder and a bearing, wherein refrigerant gas drawn into the cylinder chamber is compressed, and the refrigerant gas is discharged by opening a discharge valve provided in the bearing, it is known to a skilled person in the art that a hermetic type compressor (rotary compressor) includes a recessed portion (groove portion) formed in the bearing, a valve limiter press-fitted into the recessed portion (groove portion), and the discharge valve inserted between the valve limiter and the bearing recessed portion (groove portion) such that it is openable and closable. The valve limiter and the discharge valve each include a mounting hole, and a mounting bolt for mounting the bearing on the cylinder is inserted into the mounting holes so that the valve limiter and the discharge valve are fixedly mounted on the cylinder together with the bearing (for example, see Japanese Laid-open Patent Publication No. 08-200264).
However, according to the conventional technology described with reference to FIG. 7 to FIG. 9, as illustrated in FIG. 8, each of the bottom portions of the first and second rivet-side enlarged diameter portions 563Sa and 563Ta has a small thickness ts in entire area of the bottom portions. That is, the area having the small thickness ts is larger than the first and second discharge valves 200S and 200T and the first and second discharge-valve limiters 201S and 201T are attached to the bottom portions with the first and second rivets 203S and 203T, respectively. Therefore, when each of the first and second swaging portions 203Sa and 203Ta of the first and second rivets 203S and 203T is swaged by using the punch P, the bottom portion is deflected due to the swage load and the flatness deteriorates. Thus, the adhesiveness and the airtightness between the lower and upper end plates 160S and 160T and first and second cylinders 121S and 121T decrease.
The present invention is achieved in view of the above and has an object to obtain a rotary compressor that is capable of performing a rosette-like axial motion of a punch by a swage and includes lower and upper end plates in which bottom portions of first and second rivet-side enlarged diameter portions are not deflected.